双節棍[nunchaku] nunchaku (two linked fighting sticks)
一双[issou] pair (esp. of folding screens)
一卵性双生児[ichiranseisouseiji] identical twins
双紙[soushi] written work (esp. a bound text, as opposed to a scroll)
自己双対[jikosoutsui] self dual

双刃[moroha] double-edged
双暗車[souansha] twin propellers
双殻類[soukakurui] bivalves
双眼[sougan] both eyes

挨拶[aisatsu] greeting
挨拶回り[aisatsumawari] courtesy call
挨拶状[aisatsujou] greeting card
挨拶は抜きで[aisatsuhanukide] without compliments (greetings)
挨拶を交わす[aisatsuwokawasu] to exchange greetings

御挨拶[goaisatsu] greeting
一挨一拶[ichiaiissatsu] dialoging (with another Zen practitioner to ascertain their level of enlightenment)
時候の挨拶[jikounoaisatsu] season's greetings (conventional way of beginning a letter)
拶双魚[sappa] Japanese sardinella (Sardinella zunasi)
年頭の挨拶[nentounoaisatsu] New Year's greetings